Iran’s ultra-hard-line "Kayhan" daily, which is said to reflect the views of Supreme Leader Ayatollah Ali Khamenei, has called for a public referendum in Azerbaijan to decide whether the country should join the Islamic republic.

The call is the latest sign of deteriorating ties between Tehran and Baku and follows a March 30 conference in Baku organized by groups seeking independence for Iran’s sizable Azeri minority, which includes prominent figures such as Ayatollah Khamenei and opposition leader Mir Hossein Musavi.

Speakers at the conference, whose title has been rendered in English as "Tomorrow of the Contemporary Southern Azerbaijan," reportedly said that Iran faced a dire political future because of sanctions and international pressure, and predicted that the northwestern provinces -- which they referred to as "Southern Azerbaijan" -- will "inevitably" become independent.

Reports say the conference, which was organized by the so-called National Liberation Front of Southern Azerbaijan, was attended by activists, academics, and former Azerbaijani officials. Current Azerbaijani government officials were reportedly not present at the conference.

A participant was quoted as saying by the Turan news agency that "If the Iranian government loses control, the National Movement is ready to take control of Southern Azerbaijan."

Azeri separatists, who have little support among Iranians, refer to Iran’s East and West Azerbaijan provinces as "Southern Azerbaijan," suggesting they need to be liberated from Iran.

Swift Response

The Iranian Foreign Ministry response to the conference was swift. It summoned the Azerbaijani ambassador to Tehran and warned him that such provocations could "seriously" damage relations between the two countries.

In a letter to the ambassador, Iranian Deputy Foreign Minister for Asia and Pacific Affairs Abbas Araqchi said comments against "Iran’s sovereignty and territorial integrity" were made at the conference. "Threatening and biased words, publishing false notes and distributing offensive images in this meeting were provocative acts which only satisfy the Zionist interests," Araqchi wrote.

"Kayhan’s" managing editor, Hossein Shariatmadari -- who is thought to often speak for Khamenei -- took the dispute one step further.

In an op-ed piece titled "Baku’s Turn," Shariatmadari said Iran should step in to "save" the people of Azerbaijan by proposing to Azerbaijani officials that a referendum be held on the question of joining Iran. He called his proposal "the most basic step toward democracy."

Shariatmadari argued that Azerbaijan’s citizens see themselves as separated from the Islamic Republic of Iran and are eager to join the country.

He said the fact that only a "few" people attended the conference was proof that Azerbaijani nationals are tired of the open and hidden influence of "Zionists" in their country.

"The...conference was one of hundreds of joint measures by Zionists and some Azerbaijani officials to counter the sense of solidarity the people of Azerbaijan feel with Islamic Iran, and to prevent the outburst of these religious and cultural feelings," he wrote.

Deteriorating Relations

On April 4, Azerbaijan's Foreign Ministry addressed the controversy by saying that the views expressed at the March 30 conference don't represent the government's official position.

"Azerbaijan has repeatedly stated that it plans to continue friendly relations with Iran and does its best to strengthen them," Foreign Ministry spokesman Elman Abdullayev was quoted as saying by Azerbaijani news sites.

Relations have deteriorated in recent months over Baku’s strong ties with Israel, which sells weapons and defense equipment to Azerbaijan.

Azerbaijan has denied claims that it has agreed to allow Israel to use its bases to launch a preemptive attack against Iran’s nuclear facilities.

The conviction of a dozen people in connection with an alleged Iranian-linked spy network, and even last year’s Eurovision contest in Azerbaijan, have heightened tensions between the two neighboring, oil-rich countries.

In February 2012, Tehran accused Baku of assisting Israel’s Mossad in a series of assassinations of Iranian nuclear scientists. Azerbaijan called the accusations "absurd" and "slander."

A few months later, Iran recalled its ambassador to Baku for consultations over several protests held outside the Iranian Embassy in Baku at which demonstrators reportedly insulted Iranian officials.

The protests followed demonstrations and criticism in Iran of the Eurovision song contest, which some clerics referred to as a "gay parade."